Frequencies for continuous variables would be expressed as means ± standard deviations. Proportions would be calculated for categorical outcomes. Means would be compared using paired t-test. Chi square tests of independence would be employed for determining differences in associations. Differences in seroconversion rates and prevalence of excretion, if any, would be evaluated using ANOVA and non-parametric tests. Multiple logistic regression analysis will be undertaken to determine the nature of relationship between serum zinc status and optimal vaccine seroconversion.